Fabricating method for micro gas sensor and the same

Abstract

There are provided a micro gas sensor and a method for fabricating the same that comprises a micro heater formed inside a polysilicon membrane by doping impurities into a specific region of the polysilicon membrane positioned under a gas sensing substance, thereby improving thermal structural stability and making it easy to form the gas sensing substance. The micro gas sensor comprises: a micro heater formed by doping impurities into polysilicon vapor-deposited on a substrate on which a first insulating layer is formed; a polysilicon membrane for decreasing a heat loss of the micro heater; a power electrode for supplying power and a temperature measurement electrode for measuring a temperature, positioned at both ends of the micro heater; a second insulating layer formed on the micro heater; a sensing substance formed on the second insulating layer, for sensing a gas; and a sensing electrode for measuring a change in properties of the sensing substance. The method for fabricating a micro gas sensor comprises steps of: forming polysilicon on a substrate on which a first insulating layer is formed; forming a micro heater by doping impurities into the polysilicon; forming electrodes at both ends of the micro heater; forming a second insulating layer on the micro heater; forming a sensing substance on the second insulating layer; and forming a sensing electrode on the sensing substance.

Description

[0001]This application is a National Stage of PCT / KR 2008 / 007701 filed on Dec. 26, 2008, which claims priority of Korean Patent Application No. 10-2007-0141055 filed Dec. 28, 2007.TECHNICAL FIELD[0002]The present invention relates to a gas sensor and, more particularly, to a micro gas sensor and a method for fabricating the same that comprises a micro heater formed inside a polysilicon membrane by implanting ions or doping impurities into a specific region of the polysilicon membrane positioned under a gas sensing substance, whereby thermal stability is high and a gas sensing substance is easily and efficiently formed.BACKGROUND ART[0003]FIG. 1 is a sectional view of a conventional micro gas sensor.[0004]The conventional micro gas sensor comprises: a substrate 110, a membrane 120, a micro heater 130, an insulating layer 140, a sensing electrode 150 and a gas sensing substance 160. After the membrane 120 and the micro heater 130 are sequentially formed on the substrate 110, the insul...

AI Technical Summary

Benefits of technology

The present invention provides a micro gas sensor with a high-density array sensing substance and excellent gas sensing sensitivity. The micro heater is formed inside a polysilicon membrane by doping impurities in a predetermined concentration to the polysilicon membrane, without forming any irregular structure. The micro gas sensor has durability even for long-time operation and is easy to fabricate. The technical effects of the present invention are improved gas sensing sensitivity and durability of the micro gas sensor.

Problems solved by technology

As a result, the insulating layer 140 is broken, causing problems in electrifying the sensing electrode and the micro heater and making it difficult to maintain durability for a long time.

Then, the conventional gas sensor has the problem in that it is difficult to form the sensing substance by the contact printing method due to the irregular surface around the micro heater.

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